keg

#!/bin/bash

if [ `whoami` != "root" ]; then
	echo "No root, no keg!"
	exit 1
fi

UPD_INTERVAL=86400

CMD_DPKG=`which dpkg`
CMD_APTGET=`which apt-get`
CMD_APTCACHE=`which apt-cache`
CMD_APTFILE=`which apt-file`
[ -z $CMD_APTFILE  ] && USE_APTFILE=0 || USE_APTFILE=1
CMD_AWK=`which awk`

function check_update {

	if [[ -a ~/.keg.update && ! -f ~/.keg.update ]]; then
		echo "Aborting! ~/.keg.update is not a regular file."
		exit 1
	fi

	nextupd=0
	now=`date +%s`

	if [ -a ~/.keg.update ]; then
		nextupd=`cat ~/.keg.update` 
	fi

	if [ $nextupd -lt $now ]; then

		echo -n "Updating cache..."

		$CMD_APTGET update > /dev/null

		if [ $USE_APTFILE -eq "1" ]; then
			$CMD_APTFILE update > /dev/null
		fi

		echo "done."

		future=$(($now + $UPD_INTERVAL))
		echo $future > ~/.keg.update
	fi
}

function show_help {
cat <<EOM
Example usage:

  keg list [<filter>]
    Shows a list of all installed packages.
    If the optional filter param is given only packages matching filter is listed.

  keg install <package>
    Will download and install <package>.

  keg uninstall <package>
    Will uninstall the specified package.

  keg search <pattern>
    Will search for and list any package that matches <pattern>.

  keg provides <file>
    Will search for packages that provides the file <file>.

  keg info <package>
    Will show some information about the package.
EOM
}


case "$1" in
	list)
		$CMD_DPKG -l $2 | $CMD_AWK '{ if ( NR > 5 && $1 == "ii" ) print $2, "(" $3 ")"; }'
	;;

	install)
		check_update
		$CMD_APTGET install $2
	;;

	uninstall)
		check_update
		$CMD_APTGET --purge remove $2
	;;

	search)
		check_update
		$CMD_APTCACHE search $2
	;;

	provides)
		$CMD_DPKG -S $2 2> /dev/null
		retval=$?
		if [[ $retval != "0" ]]; then
			retval=0
			if [[ $USE_APTFILE = "1" ]]; then
				check_update
				$CMD_APTFILE search $2 | $CMD_AWK '{ print $1, $2; }END { if ( NR == 0 ) exit 1; }'
				retval=$?
			else
				echo "None of your installed packages provides $2"
				echo "If you install apt-file we could search in packages that haven't been installed."
				echo "Type: keg install apt-file to install."
			fi
		fi

		if [ $retval -gt 0 ]; then
			echo Could not find any packages providing $2
		fi
	;;

	info)
		check_update
		$CMD_APTCACHE show $2
	;;

	*)
		show_help
	;;

esac